Cand.med Eirin Esaiassen disputerer for ph.d.-graden i helsevitenskap og vil offentlig forsvare avhandlingen:
“Antibiotics and probiotics to neonates-Adverse effects, impact on gut microbiota and antibiotic resistome, and Bifidobacterium pathogenicity”
Kort sammendrag av avhandlingen:
Antibiotics are the most commonly prescribed drugs in neonatal intensive care units. Changes in the gut flora, often induced by antibiotics, are associated with development of severe gut inflammation in preterm infants. Probiotics are live bacteria associated with health benefits in humans and are associated with reduced risk of gut inflammation in preterm infants. Still, little is known about the impact of probiotics on early development of the gut flora and antibiotic-associated changes in the gut flora in preterm infants receiving probiotics. Furthermore, the potential of these live probiotic bacteria to cause infections is still unknown.
The main objective of this thesis was to systematically study the literature on potential side effects of antibiotic therapy in newborn infants, and to study the gut flora in preterm infants receiving probiotic therapy. We also studied the potential of Bifidobacterium, a commonly used group of probiotic bacteria, to cause infections in humans, including preterm infants.
In order to do this, we performed literature searches in different databases to find all the evidence of potential side-effects of antibiotic treatment in newborns. To study the effects of probiotics on the preterm infant gut flora, we performed a multi-centre study where six Norwegian hospitals participated. We recruited preterm infants given probiotics and preterm infants not given probiotics. We also recruited a small group of full term vaginally delivered healthy newborns as a control group. Stool samples were collected at 7 days, 28 days and 4 months of age and analysed using advanced techniques. To increase our knowledge about Bifidobacterium, we studied 15 patients where Bifidobacterium had caused a blood stream infection.
We found that antibiotic treatment in newborns appears to induce disease-promoting changes in the gut flora, and antibiotics given for longer periods in babies with no bacterial infections are associated with increased risk of serious gut inflammation and/or death. From our literature search, we also found that the use of broad-spectrum antibiotics is associated with increased risk of fungal infections and antibiotic resistance development, the latter also seen in our multi-centre study. In our multi-centre study, preterm infants exposed to probiotics early had high levels of Bifidobacterium compared to preterm infants not given probiotics. This finding suggests that preterm infants given probiotics may need a more gradual increase in probiotic doses to mimic their physiological gut flora development. In infants given probiotics, we found no difference in antibiotic resistance development compared to infants not given probiotics, despite the massive antibiotic exposure in the probiotic-group compared to the other infants. Our findings support the potential of probiotics to reduce the spread of antibacterial resistance and thereby infections caused by antibiotic resistant bacteria. Bifidobacterium has the potential to cause infections in humans with a weakened immune system and may cause blood stream infections. However we could not find any specific disease-causing characteristics in Bifidobacterium similar to those found in more dangerous bacteria.
(Avhandlingen er tilgjengelig for utlån hos Seksjon forutdanningstjenester frem til disputasdato)
Hovedveileder professor Claus Klingenberg, IKM, UiT
Biveileder professor Johanna Ericson Sollid, IMB, UiT
Biveileder professor Trond Flægstad, IKM, UiT
Biveileder ph.d. Pauline Cavanagh, UNN
Professor Tine Brink Henriksen, Institut for Klinisk medisin, Aarhus universitet, Danmark - 1. opponent
Docent/överläkare Stefan Johansson, Karolinska institutet, Stockholm, Sverige – 2. opponent
Professor emeritus Tore Gutteberg, Institutt for medisinsk biologi, Det helsevitenskapelige fakultet, UiT – Norges arktiske universitet – leder av komite
Førsteamanuensis Solveig Marianne Nordhov, Institutt for klinisk medisin, Det helsevitenskapelige fakultet, Universitetet i Tromsø – Norges arktiske universitet
Prøveforelesning over oppgitt emne holdes kl. 10.15, samme sted: “How to enterally feed a preterm newborn”